1. Field of the Invention:
This invention relates to superconductors that repel an element possessing a magnetic moment in accordance with the so-called Meissner effect and, more particularly, to such a superconductor that is so shaped and configured as to operate as a magnetic bottle.
2. Description of the Prior Art:
As is known in the art, a magnetic bottle employs a magnetic field that occupies a given volume of space, which magnetic field tends to prevent an element possessing a magnetic moment situated within this volume of space from escaping from this volume of space. More specifically, the field strength of a magnetic field within this volume of space is so configured that it applies a restoring force to the element in response to the element tending to move out of the given volume of space, regardless as to the direction of movement of the element. Put another way, a potential well exists within the given volume of space surrounded by a potential barrier at the boundry of the given volume of space with the exterior.
In the past, external magnets of complex design have been required to generate a magnetic field intensity spatial distribution that constitutes a magnetic bottle. Often, to provide a magnetic field exhibiting a sufficiently large potential gradient, the external magnets were comprised of superconducting electro-magnets. In this case, the Meissner effect was not employed in the operation of such superconducting electro-magnets for the purpose of deriving a magnetic bottle.
The Meissner effect, as known in the art, is the ability of a material in a superconducting state to expel all magnetic fields therefrom (i.e., such a superconductor is perfectly diamagnetic and exhibits a permeability of zero). More specifically, as known in the art, an external magnetic field, in interacting with a superconductor, is capable of penetrating the surface of the superconductor only to a so-called penetration depth of a few micrometers, at most. The result is that the magnetic-field spatial distribution is distorted by the presence of a superconductor with which it interacts. Such a distorted magnetic field contains more potential energy than it otherwise would in the absence of the superconductor.
In the past, the Meissner effect has been used to levitate a dipole magnet placed on the surface of a superconductor. The levitation force, which is directed opposite to gravity, arises from the potential gradient of the distorted (i.e., compressed) magnetic field of the dipole magnet that exists between the bottom of the levitated magnet and the surface of the superconductor with which it is interacting. Often, such levitation is used to indicate that the material underlying the dipole magnet is, in fact, operating as a superconductor.